Snake Featherston
Banned
Well, I haven't addressed how Chang wins, but-and I honestly don't know this-how close, exactly, did the Nationalists come to catching Mao during the Long March? That, to me, seems like the best moment for Chang-boom, Mao and his top leaders are dead somewhere in the wilderness in 1934, and his army is either dead, captured or thrown into complete disarray.
And also, I'd like to point out that its possible to be mildly pro-Soviet, and even receive support from the Soviets, without actually being a communist. See Nehru, Ataturk during his early rule, Nasser, and many other post-colonial leaders.
They came rather close, but that POD leaves open the problem of him defeating Mao just in time for Imperial Japan to start bitch-slapping him around and then another civil war starts later on when his weaknesses are further revealed. They were already at that time lopping off chunks of China and Jiang never really cared. On his own he's probably worse off.
A post-WWII POD, the most narrow for a GMD victory requires Stalin to stay in China longer, which requires changes to either the European War or the Manhattan Project starting a year later.